| Atmospheric microbes are mainly present in the form of aerosols in the environment.Microbial aerosols not only have extremely important ecological functions,but also closely related to atmospheric environmental quality,human health,industrial and agricultural production.In recent years,the SARS,avian flu and influenza a(H1N1)gas source on the outbreak of sexually transmitted diseases,such as frequent fog haze,dust weather,extraordinary PM2.5 values,make all countries in the world started from different angles to re-examine the potential microbial aerosol environmental safety problems.The domestic research on urban atmospheric microbial aerosols is concentrated in coastal cities,and inland cities are relatively few.Lanzhou is located in the northwest inland,dust and dust weather,geographical and meteorological conditions special.At the same time,Lanzhou as an important industrial base,physical and chemical pollution is more serious,on Lanzhou atmospheric particulate matter and chemical pollutants have been a lot of research,and atmospheric microbial aerosol pollution system research is relatively small.Sampling study of different functional areas and key polluted areas in Lanzhou was carried out by using Andersen six-stage atmospheric microbial sampler(PSW-6).The seasonal variation,monthly variation,diurnal variation of atmospheric microbial aerosol concentration and particle size distribution,and the distribution characteristics of working days and non-working days were compared in Lanzhou City,the traffic and commercial district,park area and industrial area.At the same time,select a typical sewage treatment plant and a large comprehensive hospitals in lanzhou as the key pollution area,a typical wastewater treatment plant in lanzhou different processing units(grating)between rooms,aeration tank,sludge dewatering,and a large comprehensive hospital in different functional areas(respiratory ward,ward,central garden,outpatient service hall)of the atmospheric microbial aerosol concentration and size distribution were studied.In addition,the environmental factors were recorded at the time of sampling,and the concentration of the study was correlated.Get the following conclusions:(1)The total microbial aerosol of the four seasons in the three functional areas of Lanzhou City was mixed with high to low area> Park area> Industrial area> Clean control area.The concentration of microbial aerosol in the mixed area and industrial area decreased from spring to winter,and there was no obvious change in the park area.The peak of microbial aerosol concentration in the three functional areas appeared in the autumn.The distribution trend of bacterial aerosol concentration in the third zone is the same as that of the total microbial aerosol,and its proportion is the largest in the total microbial aerosol concentration.The average concentration of fungi aerosols in the summer and autumn park area and industrial area was significantly higher than that in winter and spring,and higher than that in the same season and clean control area.The average concentration of actinomycetes in the spring and summer mixed areas and industrial areas was lower than that in the same quarter park area and the clean control area.Actinomycetes Aerosol accounts for a small proportion of total microbes in the atmosphere,while bacteria and fungi account for a large proportion.(2)The monthly variation of atmospheric microbial aerosol concentration in the mixed area,park area and industrial area was different.The total microbial aerosol concentration in the mixed zone varied from January to December with the "M" type,and peaked in June and September,and the monthly concentrations were higher than those in the other two areas.The variation curve of the industrial area is similar to that of the industrial area,but the variation range is small.The monthly average concentration of bacterial aerosol in the third zone is similar to that of the total microbial aerosol.The monthly average concentration of aerosol in the third zone showed the trend of ascending and descending from January to December,and the highest concentration appeared in September.The monthly average concentration curve of aerosol in the three areas was more complicated.From January to December,the mixed area decreased first and then decreased,and the park area and industrial area showed a decreasing trend.(3)In the spring,the aerosol concentration in the industrial area was slightly higher than that in the evening,and the diurnal variation of microbial aerosol concentration was higher in the morning,lower in the afternoon and lower in the evening.The diurnal variation of total microbial aerosol concentration in the park area and industrial area showed that the distribution of the aerosol concentration in the park area was higher than that in the mixed area,and the distribution of the early,middle and late days were higher at the higher concentration.The total microbial aerosol concentration in the third quarter of autumn was from first to late.The total microbial aerosol concentration in the early winter,middle and late mixed areas of the winter mixed area was higher than that in the park area.The total aerosol aerosol concentration reached the highest at 21:00 in the evening,and the 12: 00 ~ 15: 00 period was the lowest time for the total microbial aerosol concentration.(4)The mean value of aerosol,aerosol and actinomycete aerosol concentration in the mixed area and industrial area were higher than those in the non-working day,and the mean value of the working area in the park area was lower than that in the non-working day.(5)The average concentration of bacterial aerosol in the treatment unit and the hospital functional area was the highest,followed by fungal aerosol and the lowest aerosol of actinomycetes.The total microbial aerosol concentration from the treatment unit to the wastewater treatment unit is: sludge dewatering station> grille> aeration tank.The total microbial aerosol concentration in the functional areas of the hospital is from high to low: respiratory ward ward> outpatient hall> center garden.(6)The total microbial aerosol particle size in Lanzhou city is mainly distributed in the range of 7.0μm,4.7-7.0μm,3.3-4.7μm,and the peak value of particle size distribution is in the range of> 7.0μm.The characteristics of different seasons and different functional areas in Lanzhou have different effects on the aerosol aerosol particle size distribution.The diurnal variation of microbial aerosol particle size in the mixed zone and industrial area showed little difference in the distribution of early and late grain size,and the proportion of fine particles(<2.1μm)increased at noon.(7)The total microbial aerosol particle size in a typical sewage treatment plant in Lanzhou is mainly distributed in the range of 2.1-7.0μm.The total microbial aerosol is mainly distributed in the range of 2.1-7.0μm.The total microbial aerosol of the aeration tank is mainly distributed in the range of> 2.1μm;The total microbial aerosol in sludge dewatering is mainly distributed in the range of 1.1-7.0μm.The total microbial aerosol in the respiratory ward ward of a large general hospital in Lanzhou is mainly distributed in the range of 1.1-7.0μm,and the central garden and outpatient hall are concentrated in the range of> 2.1μm.(8)During the monitoring period of atmospheric microbial aerosol concentration in the three functional areas of Lanzhou,the concentration of aerosol in the mixed area increased with the temperature increasing in a certain range.The concentration of aerosol aerosol in the park area and industrial area increased with the temperature High and show a downward trend.The concentration of aerosol in the three functional zones increased with the increase of relative humidity,and decreased with the increase of wind speed.The concentration of microbial aerosol in the mixed and industrial areas increased with the increase of PM10 within a certain range.The aerosol concentration in the mixed area increased with the increase of PM2.5 in a certain range,and the concentration of microbial aerosol in the industrial area decreased slightly with the increase of PM2.5. |
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